The present invention relates to a surge arrester comprising a plurality of cylindrical arrester elements of metal oxide varistor material, which are arranged one after the other in the axial direction of the arrester elements and between two end electrodes in an elongated protective housing of a plastic material, which housing is resistant to deformation under the operating conditions for the surge arrester and makes contact with the envelope surfaces of the arrester elements.
In the case of a passage of current, caused by overvoltages, through a surge arrester of the above-mentioned kind, the arrester elements are heated. When the passage of current is of considerable magnitude, the temperature may amount to 150.degree.-200.degree. C. In surge arresters which are subjected to such considerable heating, the choice of protective to a housing which, nearest the arrester elements, consists of a thermosetting resin, for example an epoxy resin in the form of a casting around the arrester elements, or in the form of an epoxy resin-impregnated wrapping of a fibre material, such as a woven glass fibre, around the arrester elements. A polymer in the form of a shrinkable hose or a shrinkable tube with projections for extending creep distance may be applied on the thermosetting resin.
According to the present invention, a protective housing which is resistant to deformation under operating conditions for the surge arrester and which remains intact when subjected to the influence of arrester elements which have been heated to temperatures of the magnitude stated above, can be provided in a considerably simpler way than what has previously been possible.